Updated Upstream (Bukkit/CraftBukkit/Spigot)

Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

Please note that this build includes changes to meet upstreams
requirements for nullability annotations. While we aim for a level of
accuracy, these might not be 100% correct, if there are any issues,
please speak to us on discord, or open an issue on the tracker to
discuss.

Bukkit Changes:
9a6a1de3 Remove nullability annotations from enum constructors
3f0591ea SPIGOT-2540: Add nullability annotations to entire Bukkit API

CraftBukkit Changes:
8d8475fc SPIGOT-4666: Force parameter in HumanEntity#sleep
8b1588e2 Fix ExplosionPrimeEvent#setFire not working with EnderCrystals
39a287b7 Don't ignore newlines in PlayerListHeader/Footer

Spigot Changes:
cf694d87 Add nullability annotations

Spigot-API-Patches/Entity-getChunk-API.patch

@@ -6,15 +6,16 @@ Subject: [PATCH] Entity#getChunk API
 Get the chunk the entity is currently registered to
 
 diff --git a/src/main/java/org/bukkit/entity/Entity.java b/src/main/java/org/bukkit/entity/Entity.java
-index 13de2d74..2dd7a03c 100644
+index 373204d37..a7f81d17d 100644
 --- a/src/main/java/org/bukkit/entity/Entity.java
 +++ b/src/main/java/org/bukkit/entity/Entity.java
 @@ -0,0 +0,0 @@
  package org.bukkit.entity;
  
 +import org.bukkit.Chunk;
- import org.bukkit.Location;
++import org.bukkit.Location;
  import org.bukkit.EntityEffect;
+ import org.bukkit.Location;
  import org.bukkit.Nameable;
 @@ -0,0 +0,0 @@ public interface Entity extends Metadatable, CommandSender, Nameable {
       * @return True if entity spawned from a mob spawner
@@ -26,6 +27,7 @@ index 13de2d74..2dd7a03c 100644
 +     *
 +     * @return The current, or most recent chunk if the entity is invalid (which may load the chunk)
 +     */
++    @NotNull
 +    Chunk getChunk();
      // Paper end
  }